As spermatozoa progress along the epididymal duct they are bathed in a specialized luminal microenvironment that is crucial for their maturation and survival. In particular they need constant protection against oxidative damage and from harmful effects of drugs and xenobiotics. Oxidative injury to tissue will result in a number of pathologies including inflammatory diseases, aging, rheumatoid arthritis and is the basis in the formation of pathological obstruction within the human epididymis, resulting in male infertility. This study will examine how the expression of gamma-glutamyl transpeptidase (GGT) and dipeptidase (DP) mRNAs, two enzymes that play a critical role in the metabolism of the important antioxidant glutathione, are regulated by androgens, by factor(s) of testicular origin, and by oxidative status of the tissue. This study will focus on the proximal regions of the epididymis, the region which is influenced by testicular factors and the region highly susceptible to oxidative damage. It is proposed; (1) To examine the regulation of DP mRNA by circulating androgens. The hypothesis to be tested is that DP mRNA is differentially regulated by androgens in a region-specific manner similar to that for GGT mRNAs. (2) To determine if androgens regulate specific GGT mRNAs and DP mRNA by either changes in stability and/or changes in transcription of mRNAs. (3) To identify the testicular factor(s) that regulate GGT mRNAs and DP mRNA in the initial segment. (4) To determine if testicular factor(s) regulate specific GGT mRNAs and DP mRNA by either changes in the stability and/or transcription of mRNAs. (5) To determine if the oxidative status of the initial segment regulates the expression of specific GGT mRNAs nd DP mRNA. (6) To determine if oxidative status of the initial segment regulates specific GGT mRNAs and DP mRNA by either changes in the stability and/or transcription of mRNAs. To successfully complete all the specific aims outlined within the proposal either well established molecular biological techniques will be used alone, or in combination with in vivo micropuncture and microperfusion techniques. This laboratory is uniquely qualified to perform these studies. Therefore, this proposal will address the manner by which the epididymis regulates the genes of two important glutathione-metabolizing enzymes, GGT and DP. Both enzymes play a critical role in th regulation of glutathione a tripeptide necessary for the protection of spermatozoa against oxidative stress. This proposal is part of a long term goal to understand the mechanisms by which the epididymis maintains an optimal luminar microenvironment for sperm maturation and survival. The finding from this proposal will provide fundamental information for the treatment of certain forms of male infertility.